Regenerate MANIFEST.json when WPT tests are run

third_party/WebKit/Tools/Scripts/webkitpy/common/host_mock.py

Index: third_party/WebKit/Tools/Scripts/webkitpy/common/host_mock.py
diff --git a/third_party/WebKit/Tools/Scripts/webkitpy/common/host_mock.py b/third_party/WebKit/Tools/Scripts/webkitpy/common/host_mock.py
index dae0eb5fa8158513161b35414f63db10b83370c8..ca80562f56b6bd6215b57c8eba1efc5af4c4a9ca 100644
--- a/third_party/WebKit/Tools/Scripts/webkitpy/common/host_mock.py
+++ b/third_party/WebKit/Tools/Scripts/webkitpy/common/host_mock.py
@@ -31,6 +31,7 @@ from webkitpy.common.checkout.git_mock import MockGit
 from webkitpy.common.net.buildbot_mock import MockBuildBot
 from webkitpy.common.net.web_mock import MockWeb
 from webkitpy.common.system.system_host_mock import MockSystemHost
+from webkitpy.common.webkit_finder import WebKitFinder
 
 # New-style ports need to move down into webkitpy.common.
 from webkitpy.layout_tests.builder_list import BuilderList
@@ -54,6 +55,7 @@ class MockHost(MockSystemHost):
             time_return_val=time_return_val)
 
         add_unit_tests_to_mock_filesystem(self.filesystem)
+        self._add_base_manifest_to_mock_filesystem(self.filesystem)
         self.web = web or MockWeb()
         self._git = git
 
@@ -74,3 +76,12 @@ class MockHost(MockSystemHost):
         # Making the checkout_root exist in the mock filesystem makes that chdir not raise.
         self.filesystem.maybe_make_directory(self._git.checkout_root)
         return self._git
+
+    def _add_base_manifest_to_mock_filesystem(self, filesystem):
+        webkit_finder = WebKitFinder(filesystem)
+        wpt_dir = webkit_finder.path_from_webkit_base('LayoutTests', 'external', 'wpt')
+        filesystem.maybe_make_directory(wpt_dir)
+
+        manifest_base_path = webkit_finder.path_from_webkit_base(
+            'LayoutTests', 'external', 'WPT_BASE_MANIFEST.json')

[foolip, 2017/02/28 04:49:17]

Had an idea while looking at this line. Would it be possible to put the
generated MANIFEST.json in the same dir next to this to trivially get around it
including itself? Or even better, somewhere in the out/ directory?

Presumably the code that knows where MANIFEST.json is expected to be is under
our control so we could just change that? (If there's some upstream code that
uses the location of MANIFEST.json, that'd be a problem, but we could change
that too probably if it's the right thing.)

[qyearsley, 2017/02/28 18:54:45]

This sounds reasonable to me -- I'd be fine with this change in this CL or a
follow-up CL if you think it's a good idea. The manifest generator script takes
a --path argument which should be the path to the manifest file. The
_ensure_manifest method would still copy the base over to the manifest path and
then run the manifest generator command.

If this is done, the knowledge about where the manifest file is should be kept
in one place, probably webkitpy/w3c/wpt_manifest.py.

+        filesystem.files[manifest_base_path] = '{}'